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Paper-based biosensors are microfluidic analytical devices used for the detection of biochemical substances. The unique properties of paper-based biosensors, including low cost, portability, disposability, and ease of use, make them an excellent tool for point-of-care testing. Among all analyte detection methods, nucleic acid-based pathogen detection offers versatility due to the ease of nucleic acid synthesis. In a point-of-care testing context, the combination of nucleic acid detection and a paper-based platform allows for accurate detection. This review offers an overview of contemporary paper-based biosensors for detecting nucleic acids from pathogens. The methods and limitations of implementing an integrated portable paper-based platform are discussed. The review concludes with potential directions for future research in the development of paper-based biosensors.

INTRODUCTION: Paper currency notes, exchangeable fomite, that is continuously contaminated because of the poor handling and storage practices. Objective: the general objective of the study was to determine the bacterial contamination of paper currency notes possessed by food vendors around Mulago National Referral Hospital Complex.

Background: Global estimates for cholera annually approximate 4 million cases worldwide with 95,000 deaths. Recent outbreaks, including Haiti and Yemen, are reminders that cholera is still a global health concern. Cholera outbreaks can rapidly induce high death tolls by overwhelming the capacity of health facilities, especially in remote areas or areas of civil unrest. Recent studies demonstrated that stool specimens preserved on filter paper facilitate molecular analysis of Vibrio cholerae in resource limited settings. Specimens preserved in a rapid, low-cost, safe and sustainable manner for sequencing provides previously unavailable data about circulating cholera strains. This may ultimately provide new information to shape public policy response on cholera control and elimination. Methodology/Principal findings: Whole genome sequencing (WGS) recovered close to a complete sequence of the V. cholerae O1 genome with satisfactory genome coverage from stool specimens enriched in alkaline peptone water (APW) and V. cholerae culture isolates, both spotted on filter paper. The minimum concentration of V. cholerae DNA sufficient to produce quality genomic information was 0.02 ng/μL. The genomic data confirmed the presence or absence of genes of epidemiological interest, including cholera toxin and pilus loci. WGS identified a variety of diarrheal pathogens from APW-enriched specimen spotted filter paper, highlighting the potential for this technique to explore the gut microbiome, potentially identifying co-infections, which may impact the severity of disease. WGS demonstrated that these specimens fit within the current global cholera phylogenetic tree, identifying the strains as the 7th pandemic El Tor. Conclusions: WGS results allowed for mapping of short reads from APW-enriched specimen and culture isolate spotted filter papers this provided valuable molecular epidemiological sequence information on V. cholerae strains from remote, low-resource settings. These results identified the presence of co-infecting pathogens while providing rare insight into the specific V. cholerae strains causing outbreaks in cholera-endemic areas. [ABSTRACT FROM AUTHOR]

• A cost-effective and eco-friendly polyDOPA@paper was prepared for DNA extraction. • The adsorption capacity of polyDOPA@paper for DNA was 20.7 μg cm−2. • An automated extraction system was designed to ensure results consistency. • The DNA extraction platform averts the need for specialized training of operators. • The platform combined with qPCR realized the detection of E. coli in milk samples. The success of polymerase chain reaction (PCR) depends on the quality of deoxyribonucleic acid (DNA) templates. This study developed a cost-effective and eco-friendly DNA extraction system utilizing poly(3,4-dihydroxyphenylalanine)-modified cellulose paper (polyDOPA@paper). PolyDOPA@paper was prepared by oxidatively self-polymerizing DOPA under weak alkaline conditions and utilizing the adhesive property of polyDOPA on different materials. Compared to the uncoated cellulose paper, polyDOPA coating significantly enhances DNA adsorption owing to its abundant amino, carboxyl, and hydroxyl moieties. The DNA extraction mechanism using polyDOPA@paper was discussed. The maximum adsorption capacity of polyDOPA@paper for DNA was 20.7 μg cm−2. Moreover, an automated extraction system was designed and fabricated using 3D printing technology. The device simplifies the operation and ensures the reproducibility and consistency of the results. More importantly, it eliminates the need for specialized training of operators. The feasibility of the polyDOPA@paper-based automated extraction system was evaluated by quantitatively detecting Escherichia coli in spiked milk samples via a real-time PCR. The detection limit was 102 cfu mL−1. The results suggest that the system would have significant potential in detecting pathogens. [ABSTRACT FROM AUTHOR]

Background: The use of filter paper as a simple, inexpensive tool for storage and transportation of blood, ‘Dried Blood Spots’ or Guthrie cards, for diagnostic assays is well-established. In contrast, there are a paucity of diagnostic evaluations of dried cerebrospinal fluid (CSF) spots. These have potential applications in low-resource settings, such as Laos, where laboratory facilities for central nervous system (CNS) diagnostics are only available in Vientiane. In Laos, a major cause of CNS infection is Japanese encephalitis virus (JEV). We aimed to develop a dried CSF spot protocol and to evaluate its diagnostic performance using the World Health Organisation recommended anti-JEV IgM antibody capture enzyme-linked immunosorbent assay (JEV MAC-ELISA). Methodology and Principal Findings: Sample volumes, spotting techniques and filter paper type were evaluated using a CSF-substitute of anti-JEV IgM positive serum diluted in Phosphate Buffer Solution (PBS) to end-limits of detection by JEV MAC-ELISA. A conventional protocol, involving eluting one paper punch in 200μl PBS, did not detect the end-dilution, nor did multiple punches utilising diverse spotting techniques. However, pre-cut filter paper enabled saturation with five times the volume of CSF-substitute, sufficiently improving sensitivity to detect the end-dilution. The diagnostic accuracy of this optimised protocol was compared with routine, neat CSF in a pilot, retrospective study of JEV MAC-ELISA on consecutive CSF samples, collected 2009–15, from three Lao hospitals. In comparison to neat CSF, 132 CSF samples stored as dried CSF spots for one month at 25–30°C showed 81.6% (65.7–92.3 95%CI) positive agreement, 96.8% (91.0–99.3 95%CI) negative agreement, with a kappa coefficient of 0.81 (0.70–0.92 95%CI). Conclusions/Significance: The novel design of pre-cut filter paper saturated with CSF could provide a useful tool for JEV diagnostics in settings with limited laboratory access. It has the potential to improve national JEV surveillance and inform vaccination policies. The saturation of filter paper has potential use in the wider context of pathogen detection, including dried spots for detecting other analytes in CSF, and other body fluids. [ABSTRACT FROM AUTHOR]

Paper-based biosensors are microfluidic analytical devices used for the detection of biochemical substances. The unique properties of paper-based biosensors, including low cost, portability, disposability, and ease of use, make them an excellent tool for point-of-care testing. Among all analyte detection methods, nucleic acid-based pathogen detection offers versatility due to the ease of nucleic acid synthesis. In a point-of-care testing context, the combination of nucleic acid detection and a paper-based platform allows for accurate detection. This review offers an overview of contemporary paper-based biosensors for detecting nucleic acids from pathogens. The methods and limitations of implementing an integrated portable paper-based platform are discussed. The review concludes with potential directions for future research in the development of paper-based biosensors. [ABSTRACT FROM AUTHOR]

Biomaterial-implants are frequently used to restore function and form of human anatomy. However, the presence of implanted biomaterials dramatically elevates infection risk. Paradoxically, dental-implants placed in a bacteria-laden milieu experience moderate failure-rates, due to infection (0.0-1.1 %), similar to the ones of joint-arthroplasties placed in a near-sterile environment (0.1-1.3 %). Transcutaneous bone-fixation pins breach the immune-barrier of the epidermis, exposing underlying sterile-tissue to an unsterile external environment. In contrast to dental-implants, also placed in a highly unsterile environment, these pins give rise to relatively high infection-associated failure-rates of up to 23.0 %. Herein, we attempt to identify causes as to why dental-implants so often succeed, where others fail. The major part of all implants considered are metal-made, with similar surface-finishes. Material choice was therefore discarded as underlying the paradox. Antimicrobial activity of saliva has also been suggested as a cause for the success of dental-implants, but was discarded because saliva is the implant-site-fluid from which viable bacteria adhere. Crevicular fluid was discarded as it is largely analogous to serum. Instead, we attribute the relative success of dental-implants to (1) ability of oral tissues to heal rapidly in the continuous presence of commensal bacteria and opportunistic pathogens, and (2) tolerance of the oral immune-system. Inability of local tissue to adhere, spread and grow in presence of bacteria and an intolerant immune-system are identified as the likely main causes explaining the susceptibility of other implants to infection-associated failure. In conclusion, it is the authors’ belief that new anti-infection strategies for a wide range of biomaterial-implants may be derived from the relative success of dental-implants.

Introduction: Paper currency notes, exchangeable fomite, that is continuously contaminated because of the poor handling and storage practices. Objective: the general objective of the study was to determine the bacterial contamination of paper currency notes possessed by food vendors around Mulago National Referral Hospital Complex. Methods: A total of sixty paper notes of six denominations (1000, 2000, 5000, 10000, 20000, 50000) were collected from different food vendors. Each note was preserved in a sterile falcon tube and transported to the microbiology lab for bacteriological examination. Data from questionnaires was analyzed using SPSS version 23 (IBM SPSS Statistics). Results: All sampled paper notes had bacterial contamination. The bacterial counts ranged from 4×102cfu/ml to 6.8×109 cfu/ml, with the Shs.1000 notes having the highest average total bacterial load of 2.17×109 cfu/ml and highest average total coli form counts of 21.5×102 cfu/ml. The fifty thousand shillings note had no coliform detected. Of the analysed 60 samples, 27(45%) samples contained Staphylococcus aureus. None of the sampled paper notes had Escherichia coli. Conclusion: The study revealed that most of Ugandan paper notes are contaminated with bacteria including potential pathogens that cause disease in healthy individuals and opportunistic pathogens that may cause disease in hospitalized and immunocompromised patients. This study showed that the most contaminated note denominations were those of low denomination (Shs.1000 and Shs.2000) which had the highest bacterial count. The study revealed the paper currency notes were stored in different places where the commonest was the drawer and kept with different items, the commonest being pens. Hence, great care must be taken while handling money during the preparation and handling of food to avoid cross contamination. [ABSTRACT FROM AUTHOR]

Background: The lack of information regarding the burden of acute bacterial meningitis in Latin America leads to a reduction in the estimated incidence rates of the disease, and impairs public health decisions on the use and follow-up of preventive interventions, particularly, the evaluation of existing vaccination policies. The use of the real-time PCR in diagnostic routine procedures has resulted in a substantial increase in confirmed bacterial meningitis cases. However, in resource-poor countries, these assays are only available in reference laboratories. Sample transportation to these laboratories is a critical constraint, as it requires specialized, high cost courier services. To overcome this barrier we evaluated the use of FTATM Elute filter paper cards for the conservation and processing of samples under normal environmental conditions, as they would be when transported from remote and under-equipped healthcare facilities to the reference centers. A total of 401 samples received in 2015 as part of Sao Paulo’s national surveillance for routine diagnosis were selected for this study. Methods: The sensitivity and specificity of real-time PCR were evaluated using fresh serum and cerebrospinal fluid (CSF) samples processed using our laboratory’s standard DNA extraction, and processing the same samples after being dried and stored on FTATM card, and DNA extracted following the manufacturer’s instructions. Results: The sensitivities for detection of Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae from CSF dried and stored on FTATM cards were 98%, 92%, and 100%, respectively, and with serum samples were 73%, 88%, and 100%, respectively. When compared to our laboratory’s standard methodology, results showed high concordance, with Kappa index ranges of 0.9877–1.00 for CSF, and 0.8004–1.00 for serum samples. Conclusion: The use of FTATM cards for CSF and serum conservation and transport represents a rapid, reliable, and cost-effective alternative that will allow obtaining valuable epidemiological information that would otherwise be lost. [ABSTRACT FROM AUTHOR]

Pyocyanin is a toxin produced by Pseudomonas aeruginosa. Here we describe a novel paper-based electrochemical sensor for pyocyanin detection, manufactured with a simple and inexpensive approach based on electrode printing on paper. The resulting sensors constitute an effective electrochemical method to quantify pyocyanin in bacterial cultures without the conventional time consuming pretreatment of the samples. The electrochemical properties of the paper-based sensors were evaluated by ferri/ferrocyanide as a redox mediator, and showed reliable sensing performance. The paper-based sensors readily allow for the determination of pyocyanin in bacterial cultures with high reproducibility, achieving a limit of detection of 95 nM and a sensitivity of 4.30 μA/μM in standard culture media. Compared to the similar commercial ceramic based sensors, it is a 2.3-fold enhanced performance. The simple in-house fabrication of sensors for pyocyanin quantification allows researchers to understand in vitro adaptation of P. aeruginosa infections via rapid screenings of bacterial cultures that otherwise are expensive and time-consuming. [ABSTRACT FROM AUTHOR]

Microorganisms are known to spread via air, water, food etc. an important mechanism of the spread of pathogens by formites. Food, water and soil borne infection are estimated to be affecting almost half of the world population. Paper currency notes which are transferred from one individual to other are known to carry bacteria on their surface and are responsible for transmitting them. These notes are susceptible to bacterial contamination during contaminate handing from person to person. An individual living in unhygienic conditions having unhygienic habits will contaminate the notes with bacteria e.g. habits such as using soling to count the paper notes also leads to the contamination and these notes will act as a vehicle delivering bacteria to contaminate the hands of the next user. Diseases continue to be a cause of major concern to human health in several part of the globe including in India, causing high morbidity, mortality and economic losses. Diseases that are transmittable contribute to paper currency this statistics by affecting human health and causing heavy looses directly or indirectly to economy. The aim of the present study was to ascertain the incidence and transmittance of microbes analysis from the paper currency collected from different regions of Ajmer and the presence of Escherichiacoli, Enterobacter spp. has been observed in the studied samples thereby highlighting the role of paper currency in spread of diseases. [ABSTRACT FROM AUTHOR]

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The meat industry requires prompt and effective control measures to guarantee the quality and safety of its products and to avert the incidence of foodborne illnesses and disease outbreaks. Although standard microbiological methods and conventional analytical techniques are employed to monitor the quality and safety, these procedures are tedious and time-consuming, require skilled technicians, and sophisticated instruments. Therefore, there is an urgent need to develop simple, fast, and user-friendly hand-held devices for real-time monitoring of the quality of meat and meat products in the supply chain. Biosensors and chemical indicators, due to their high sensitivity, specificity, reproducibility, and stability, are emerging as promising tools and have the potential for monitoring and controlling the quality (freshness and sensory traits such as tenderness) and safety (metabolites, contaminants, pathogens, drug residues, etc.) of muscle foods. In this review, the application of biosensors in the meat industry and their emerging role in the quantification of key meat quality components are discussed. Furthermore, the role of different biosensors to identify and detect contaminants, adulterants, pathogens, antibiotics, and drug residues in meat and meat products is also summarized. [ABSTRACT FROM AUTHOR]

Conventional techniques (e.g., culture-based method) for bacterial detection typically require a central laboratory and well-trained technicians, which may take several hours or days. However, recent developments within various disciplines of science and engineering have led to a major paradigm shift in how microorganisms can be detected. The analytical sensors which are widely used for medical applications in the literature are being extended for rapid and on-site monitoring of the bacterial pathogens in food, water and the environment. Especially, within the low-resource settings such as low and middle-income countries, due to the advantages of low cost, rapidness and potential for field-testing, their use is indispensable for sustainable development of the regions. Within this context, this paper discusses analytical methods and biosensors which can be used to ensure food safety, water quality and environmental monitoring. In brief, most of our discussion is focused on various rapid sensors including biosensors and microfluidic chips. The analytical performances such as the sensitivity, specificity and usability of these sensors, as well as a brief comparison with the conventional techniques for bacteria detection, form the core part of the discussion. Furthermore, we provide a holistic viewpoint on how future research should focus on exploring the synergy of different sensing technologies by developing an integrated multiplexed, sensitive and accurate sensors that will enable rapid detection for food safety, water and environmental monitoring.

Paper-based sensors can be exploited to develop low-cost, disposable, and rapid assays for the detection of a large variety of analytes. We report a paper-based sensor system for a point-of-care (POC) nucleic acid amplification test that can quantitatively detect multiple genes from different pathogens. The POC system combines a paper sensor chip and a portable instrument, which is built on an Internet of Things (IoT) platform. The paper-based sensor provides the functions of reagent storage, sample transportation, and nucleic acid amplification. The IoT instrument uses an Arduino microcontroller to control temperature, collect fluorescence images, and store the data in cloud storage via a WiFi network. A compact fluorescence reader was designed to measure fluorescence images of the amplicons during a loop-mediated isothermal amplification reaction in real-time. The real-time detection capability enables the quantitative analysis of target genes. The results show that the paper-based sensor cam distinguish multiple genes of the genomic DNA extracted from Escherichia coli and Campylobacter jejuni, with the concentration as low as 2 × 103 copies/μL. The affordable instrument, in conjunction with the disposable paper sensor chip, would have a great potential for POC detections of pathogens. • Quantitative detection of target genes in paper by real-time analysis of fluorescence images. • Storage of PCR reagents and primer sets in paper for point-of-care applications. • Simultaneous detection of multiple genes from different bacterial strains. • A fully automated, low-cost, and compact instrument. [ABSTRACT FROM AUTHOR]

Background: Currency notes represent a universal medium for transmission of bacteria in the environment and among humans. Care should be taken by those handling these currencies. Aim: To quantitatively assess and compare the total bacterial load of Staphylococcus aureus, Escherichia coli, and Proteus species present on the currency notes circulating in the open market area and hospitals in Mangalore city. Methodology: A total of 24 frequently circulated currency notes were collected from open markets and hospitals (12 from each group). They were then deposited in sterile pouches. Samples were collected using moistened cotton swabs and inoculated onto MacConkey agar for bacterial growth. The isolated bacteria were then assessed for the percentage of bacteria and colony-forming units (CFUs) on the notes using standardized microbial analysis. Results: Cultures after microbial analysis showed bacterial contamination with S. aureus, E. coli, Klebsiella, and aerobic spore-bearing bacteria. Approximately >103 CFUs/plate were found. In the hospital group, isolated organisms comprised S. aureus (54%) and E. coli(25%); in the open market areas, E. coli(36%) and S. aureus (38%) were found. Proteus species were not present on any of the samples. Intergroup statistical analysis carried out using the Chi-square test was statistically significant (P = 0.034). Conclusion: The study concluded that the notes from hospitals were contaminated more with S.aureus than in open markets, whereas E. coli was found to be more in open market areas than in hospitals.

Contaminated fresh produce remains a prominent catalyst for food-borne illnesses, prompting the need for swift and precise pathogen detection to mitigate health risks. This paper introduces an innovative strategy for identifying food-borne pathogens in fresh produce samples from local markets and grocery stores, utilizing optical sensing and machine learning. The core of our approach is a photonics-based sensor system, which instantaneously generates optical signals to detect pathogen presence. Machine learning algorithms process the copious sensor data to predict contamination probabilities in real time. Our study reveals compelling results, affirming the efficacy of our method in identifying prevalent food-borne pathogens, including Escherichia coli (E. coli) and Salmonella enteric, across diverse fresh produce samples. The outcomes underline our approach’s precision, achieving detection accuracies of up to 95%, surpassing traditional, time-consuming, and less accurate methods. Our method’s key advantages encompass real-time capabilities, heightened accuracy, and cost-effectiveness, facilitating its adoption by both food industry stakeholders and regulatory bodies for quality assurance and safety oversight. Implementation holds the potential to elevate food safety and reduce wastage. Our research signifies a substantial stride toward the development of a dependable, real-time food safety monitoring system for fresh produce. Future research endeavors will be dedicated to optimizing system performance, crafting portable field sensors, and broadening pathogen detection capabilities. This novel approach promises substantial enhancements in food safety and public health. [ABSTRACT FROM AUTHOR]

Natural components isolated from spices are gaining the attention of food researchers to prevent the growth of microbes associated with food spoilage and foodborne pathogenesis to meet the ever-increasing consumers' demand for safe and wholesome food free from harmful synthetic preservatives. In the present study, five bioactive components of spice origin, namely, allylisothiocyanate (AITC), cinnamic aldehyde (CIA), cuminic aldehyde (CUA), eugenol (EU), and menthol (MT) were evaluated for their antimicrobial potential towards six bacterial strains (Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Pseudomonas alcaligenes, Shigella sonnei, Staphylococcus aureus) and eleven fungal strains (Alternaria solani, Aspergillus niger, Botrytis cinerea, Cladosporium herbarum, Fusarium oxysporum, Geotrichum candidum, Penicillium citrinum, Penicillium expansum, Phoma exigua, Rhizopus arrhizus and Rhizopus stolonifer), by opting agar well diffusion assay, impregnated paper disc method and broth dilution technique. All these seventeen microbes pose deleterious effects on food and human health. Among the bioactive compounds, CIA and CUA turned out to be the most potent inhibitors of microorganisms, whereas MT was found to be the least effective. Lower concentrations of bioactive components, ranging from 1.95 µL/mL to 15.62 µL/mL, were needed to inhibit fungi, while higher concentrations ranging from 15.62 µL/mL to 1000 µL/mL were needed to inhibit bacterial strains. Among the bacterial strains tested, gram-negative bacteria were inhibited at higher component concentration levels (31.25 µL/mL-1000 µL/mL) compared to gram-positive bacteria. The present study updates the existing information on the antimicrobial potency of natural substances, paving the way to further research on establishing spice bioactive components as 'natural additives'. [ABSTRACT FROM AUTHOR]

The paper presents the behaviour of some wheat varieties under the years 2014, 2016, 2018, 2019, 2020, 2023 conditions in Dobrogea area in demonstrative plots carried out at S.C. SPORT AGRA S.R.L. Amzacea, Constanta County. The main aspects emphasized in this research area have been: climatic conditions, obtained yield, and economical efficiency. Looking to the pathogens, for wheat Septoria tritici showed an AR between 17-27% and Pyrenophora graminea showed a low atack (AR = 4.5-17.5%). The pathogen Puccinia striiformis was present in low precentage (AR = 0-13.5%) in the 2018 April observations. For crop protection against pathogens, 2 foliar tratments with fungicides were applied, Artea 330 EC(ciproconazol 80 g/l + propiconazol 250 g/l) 0,4 l/ha, in March and Priaxor EC (fluxapiroxad 150 g/l + piraclostrobin 75 g/l) 1l/ha and in April respectively. Fungal treatments have stopped the development of foliar and ear diseases. The beneficial effects were found in the good yields obtained in 2014, 2016, 2018, 2019, except the years 2020 and 2023. In 2020 Otilia reached 2,370 kg/ha, Miranda 2,260 kg/ha and Solindo variety 4,297 kg/ha and Ursita 4,165 kg/ha in 2023. All these special yields have been obtained under non-irrigated conditions. [ABSTRACT FROM AUTHOR]